SSD Host-Initiated Buffer Flushing for Low Power State Entry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mass storage devices face challenges in achieving low power consumption while maintaining high performance, as the design improvements for faster operation, such as cache-like buffers, prevent the device from entering a low power sleep mode due to the need for continuous flushing of buffers during idle time.
Innovation Solution
Implementing host-initiated buffer flushing, where the host system commands the SSD to perform flushing operations during active periods, allowing the device to enter a low power state by interleaving flushing with read/write requests, thereby optimizing power usage and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a cache-like buffer is implemented to improve write access speed, then write performance is improved, but the device cannot enter low power sleep mode because the buffer must be continuously flushed during idle time
Solution Approach 1:
The host system initiates buffer flushing operations before the SSD needs to enter sleep mode, ensuring data is already flushed when idle time arrives. This preliminary action allows the SSD to safely enter low power states without risking data loss, resolving the contradiction between maintaining fast write access (buffer usage) and reducing power consumption (sleep mode capability).
Solution Approach 2:
Instead of continuous flushing, the buffer flushing is performed periodically or on-demand based on host initiation. This allows the SSD to alternate between active flushing periods and low power sleep periods, achieving both fast write performance during active periods and reduced power consumption during idle periods.
2Reliability
If buffer flushing is performed during idle time to maintain data integrity, then data reliability is improved, but the device remains awake longer and consumes more power
Solution Approach 1:
The host initiates buffer flushing operations in advance before the SSD needs to transition to sleep mode. This ensures data integrity is maintained while allowing the SSD to enter low power states promptly after flushing completes, minimizing energy loss during idle time.
Solution Approach 2:
The SSD provides feedback to the host about buffer status and flushing completion, allowing the host to intelligently initiate flushing operations at optimal times. This feedback mechanism ensures data reliability while coordinating with the host's power management decisions to minimize energy consumption.
3Productivity
If the SSD maintains a large buffer to handle write requests faster, then productivity is improved, but the complexity of managing buffer flushing increases
Solution Approach 1:
The host system takes responsibility for initiating buffer flushing operations based on its own knowledge of workload patterns and power management needs. This self-service approach reduces the SSD's burden for managing buffer flushing complexity while maintaining high write throughput through the SSD's large buffer capability.
Solution Approach 2:
Instead of implementing complex automatic flushing algorithms, the system uses simple host-initiated flushing that may be slightly excessive (flushing more frequently than absolutely necessary) but is much easier to implement and manage. This partial action approach maintains productivity while significantly reducing device complexity.
Data Source
AI summary
An apparatus is described that includes a solid state drive having non volatile buffer memory and non volatile primary storage memory. The non volatile buffer memory is to store less bits per cell than the non volatile primary storage memory. The solid state drive includes a controller to flush the buffer in response to a buffer flush command received from a host. The controller is to cause the solid state drive to service read/write requests that are newly received from the host in between flushes of smaller portions of the buffer's content that are performed to service the buffer flush command.